1. Field of the Invention
The present invention relates to a haymaking machine, particularly to a windrower for mown plant matter, comprising a frame with three raking windrowing wheels, which raking wheels are driven during work about substantially vertical axes and can be configured into a position of minimum space-occupancy for transport that does not exceed the heights and widths permissible for travel on the public highway.
2. Discussion of the Background
Various windrowers having several raking wheels are already known and used in agricultural concerns, these machines usually forming several windrows, one per raking wheel, and having a working width that is directly dependent on the number of raking wheels and on the diameter thereof.
Windrowers comprising raking wheels aligned at right angles to the direction of travel are known from document EP 465 393 or EP 1 142 468. All these machines propose folding the raking wheels vertically, in a position at 90° with respect to the work position for the transport of the machine. This transport configuration may lead to the folded machine having a significant height and consequently occupying an important amount of space that is incompatible with the roadways that are to be used.
Indeed, given the permissible heights and widths for these public highways, arrangements have to be made for the machine to be transported as an “exceptional load”, which entails an additional vehicle equipped with a flashing light and the requisite personnel. This type of expensive displacement has to be planned ahead, and this is not always possible for the farmer to achieve, particularly if he is working alone.
For reasons of productivity it is also desirable to produce large-capacity windrowers which are able to gather the fodder together in a single windrow collected from the largest possible area of ground, namely a machine that allows a minimum number of passes over the field, these machines are therefore designed with raking wheels of large diameter and the number of which is as high as is technically feasible.
These large-capacity windrowers therefore present problems of transport when moving them from one working space to another along the public highway.
As already mentioned, there are windrowers that have raking wheels that are aligned in a plane perpendicular to the direction of forward travel of the tractor, these machines are restricted in terms of dimensions because of the folding configurations that can be achieved and because of their design which does not allow the fodder to be gathered together into a single large windrow per pass.
In consequence, the compromise that can be reached between the size of the machine, particularly the size of the raking wheels, against the need to transport the machine easily from one work site to another, and against the number of windrows formed is very unfavorable for windrowers of this type.
Machines with raking wheels offset in the opposite direction from the direction of travel of the tractor in order to collect several zones in a single pass and gather them together into a single windrow have been conceived. This way of raking the field allows the number of passes of the machine tasked with the subsequent collection of the fodder to be reduced.
An example of such a windrower with offset raking wheels is described in document EP 1 290 936, although, as in the case of the in-line raking wheels described earlier, a compromise has to be reached between the permissible length of the machine coupled behind the tractor and the number of raking wheels that can be set out in this way. The problem of siting a large number of raking wheels on the machine while having the most compact transport configuration possible still arises.